How do you bind a class or style conditionally?
In Svelte, you can conditionally apply classes or styles based on a variable or expression. This is useful for dynamically changing appearance in response to state changes.
Example: Conditional Class
Here, the class is-active is added to the <button> only when isActive is true. Clicking the button toggles the state and the class.
Example: Multiple Classes
Example: Conditional Styles
Best practices for conditional classes and styles:
Use
class:name={condition}for conditional class application.For multiple dynamic classes, combine several
class:name={condition}directives.Inline styles can be conditionally set using Svelte’s template expressions inside
styleattributes.Prefer class binding over inline styles for maintainable and reusable CSS.
Reactive statements (
$:) can be used to compute style or class values dynamically.